1. Field of the Invention
This invention relates to organic dye lasers and more particularly to dye laser solutions. Even more particularly, this invention relates to the use of surfactants to improve the performance of non-flowing dye laser systems.
2. Description of the Prior Art
Liquid dye laser systems using conventional solvents require a reservoir of dye solution for circulation through the dye cell. A pumping network adds to the system complexity and size but is necessary to maintain the necessary flow and temperature to prevent premature breakdown of the laser dye.
Additives to the dye solution which would assist in energy transfer between dye molecules would lead to more efficient lasers. This would reduce the volume of dye solution needed for operation of the dye laser. In turn, this would make liquid dye lasers more efficient, simple and compact thereby providing additional applications that are not presently possible.
Surfactants are known to aid in preventing the dimerization of laser dye molecules, yielding a more uniform monomer solution. However, excess dye molecules not combined with surfactant could result in formation of ground state aggregates, causing increased absorption at the lasing wavelength and quenching by eximer formation. It is also known that, for a fixed concentration of surfactant, an increase in the concentration of certain types of dye molecules will lead to an increase in the number of these dye molecules per micelle if conditions for micelle formation, solvent and dye molecules have satisfied certain requirements.
Surfactant additives have been used with low viscosity solvents in flowing dye laser systems. Increases in fluorescence yield in such systems have been measured. This improvement has been attributed to the above described surfactant effects on dimerization and dye concentration effects on the number of dye molecules per micelle.
Solvent viscosity is known to affect the formation and properties of micelles. It is also known that certain viscous solvents have thermal and optical properties which would be useful in a non-flowing liquid dye laser system. However, significant increases in laser dye output, conversion efficiency, and laser dye lifetime resulting from certain combinations of surfactants and viscous polar solvents are quite unexpected and are not obvious from the prior art.